1. Field of the Invention
The present invention relates to a battery assembly with high thermal conductivity and, more particularly, to a highly thermal conductive battery suitable for use in a battery engine of an electric-powered vehicle.
2. Description of Related Art
The presence of battery technologies initiates the domination over electric power by human kind. From the Leyden jar and voltaic pile to the modern lithium-ion battery, it is possible now to provide electric power of greater magnitude and higher power when people separate themselves from a power supply area, thus allowing utilization of machines and tools requiring high power. Safety issues on batteries in electronic communication products such as general mobile phones or computers often attract people's attention through news broadcasts, but the battery installed within such electronic devices in fact usually contains only one battery core or probably at most three. Comparatively, for driving large-scaled electric-consuming appliances like electric-powered vehicles, usually it requires a battery array, composed of a greater amount of batteries connected in serial or in parallel, to supply electric power of high voltage and mega-current.
However, upon connecting together a large amount of batteries, the massive heat generated when the mega-current flows through resistors may become very challenging for operation of the battery set. On one hand, the elevated temperature may reduce the conductivity in the metal, such that the power supply deviates from a predetermined range. On the other hand, such a temperature increase may also cause the battery cores to swell, resulting in undesirable mutual squeezing among adjacent battery cores thus leading to increased risks of rupture, battery solution leakage or even combustion or explosion. In a worse case, once battery core breakup or battery solution leakage indeed occurs in any one of the battery cores, short-circuit problem of adjacent battery cores may accordingly happen thus leading to unexpected instantaneous release of massive electric current. Therefore it has been one of major research subjects for the industry to effectively dissipate such generated heat.
FIG. 1 shows a common heat dissipation design that provides a solution to the problems described above, wherein each battery 2 is provided with heat sink cooling fins at its lateral sides, thereby further creating gaps among neighboring batteries 2. Using forced air convections through air blow generated by a fan 20, it is possible to carry heat energy away from the lateral sides of batteries 2 and the cooling fins. Unfortunately, in a conventional lithium secondary battery or a like battery, metallic material and thermal conductive material are mainly mounted along the direction from the top face 21 to the bottom face 22, but the battery solution with poor heat conductivity is filled within the space between the central axis of the battery core and the lateral sides, thus significantly increasing the heat resistance thereof. In other words, even though the distance between the top face and the bottom face is much greater than that between the opposite lateral sides, heat conductivity for the battery core toward its top face and bottom face is more efficient than toward the lateral faces. Consequently, heat dissipation in the aforementioned process, no matter through cooling fins or forced convections, is mostly addressed to the portions with poor thermal conductivity or limited heat accumulation capability, rather than areas where the most effective heat removal feature can be offered.